Blasting cartridge



May 1Q, H SZ. F. H. KNEELAND BLASTING CARTRIDGE Fileu. Oct. 24, 1929 .2720 62220 2' frarL Zlizaee lag/ 0 Patented ar -1G, 1932 FRANK H. KNEELAND, OF CHICAGO, ILLINOIS, ASSIGNOR TO SAFETY MINING COMPANY,

OF CHICAGO, ILLINOIS, A CORPORATION BLASTING CARTRIDGE Application filed October 24, 1929. Serial No. 402,018.

. The present invention is concerned with re chargeable blasting cartridges of the type wherein a compressed gas is employed as the blasting medium and means is provided for increasing the pressure sufficiently to cause rupture of some part of the cartridge, whereby the-confined blasting medium is liberated. The principal object of the invention is to simplify blasting cartridges of this character.

Specifically, it is an obj ect of the invention to provide a simplified method and means for releasing a confined charge of a blasting medium.

A further object is to provide a blasting cartridge, the capacity of which may be readily changed.

In the drawings:

Figure 1 is a View in longitudinal section of a blasting cartridge exemplifying my invention, and

Figure 2 is a detail view of one of the elements shown in Figure 1.

The improved cartridge comprises two main parts which for convenience may be termed a primary part 1 and a secondary part 2. These parts are formed with chambers 3 and 4 respectively. The primary part 1 is reduced in diameter at its end as indicated at 5 and the exterior surface of this reduced portion is provided with screw threads. The corresponding end of the secondary member 2 is likewise provided with screw threads but as may be noted in the drawings, these threads are not designedfor direct engagement. Interposed'between the threaded portions of the members 1 and 2 is a rupturable connector member 6, which, in the form shown, is a sleeve-like member provided with both internal and external threads. This connector member may be formed of any suitable material, preferably a relatively soft material, such, for exmple, as lead or Babbitt metal. However, it should be understood that the connector member may be formed of non-metallic substances having the necessary strength.

The primary member 1 is provided at its closed end with an insulated electrode 7 a charging valve 8 and a protector cap 9. The valve 8 servesto control the admission of gas or other blasting medium through the charging port 10 into the interior oi the cartridge.

This type of cartridge usually employs an electrically energized heat producing unit such as is indicated at 11. This unit isdesigned to have contact at one end with the metallic body of the cartridge and at its other end with the insulated electrode 7. A source of electricity. may be connected to the cartrid'ge by means of a contact plug engageable with the end of the electrode'7 and a wire or other conductor secured through one or more apertures 12 formed in the protector cap.

Thus, there is established a complete circuit from the cartridge body through the heater and back to the electrode. r The prlnciple of operation is that a charge of compressed gas or the like is introduced into the chamber formed by the primary and secondary members 1- and 2 and this charge is thereafter expanded by means of the heat given off by the heater unit 11 with the result that the-internal pressure is built up to the point of rupture of some portion of the cartridge. In the present-construction the connector member 6 is designed to be the rupturable member which gives way. when the blasting pressure within the cartridge has been reached. I Thus, the rupture of the connector 6 serves to permit the separation of the primary and secondary members 1 and 2 thereby permitting the discharge of gas through the open end of each of these members. In this way the gas is very rapidly discharged from'the cartridge. It will be understood, of course, that a new connector .member must be used after each discharge of a cartridge.

Another feature of the present construction is that the separation of the body of the cartridge into two main parts gives rise to the possibility of readily providing cartridges of difierent capacities by merely providing a plurality of secondary parts of different sizes. Thus, the secondary part 2 of the present construction is of simple cylindrical formation with a semi-spherical closed end and it is intended that this member of the cartridge be provided in a plurality of ditferent sizes in order to provide the desired variation in capacities. It will be apparent that the major cost of: the cartridge herein disclosed is in connection with the production of the primary member 1 and the various parts carried by it. Thus, both the valve and electrode, as Well-as the protector cap are provi ded in the primary .1. This leaves the sec ondary member of extremely simple construction; L Thus, the costly portion of the cartridge may be made in a single size only, but may be associated with secondary parts of. a plurality of diiferent sizes in orderto provide a variety of capacities.

I claim: j 1

1., blasting cartridge comprising a two part cylinder, the open end of one part extending into the open end of the other part, external threads'iormed on the said one part,

internal threads formed on the said other part, said threads ,being arranged out of en- T gagement and in opposed relation, and ampturable connector having internal and external threads arranged between and joining said parts.

2. A- blasting cartridge comprising a sub stantially indestructible metallic casing adapted to contain a blasting mediumysaid casing consisting of separable sections, and means connecting adjacent ends of said sections and designed to rupture in response to a predetermined pressure within the casing and permit separation of said sections and liberate the blasting medium.-

3. A blasting cartridge comprising an indestructible metallic casing consisting of axially separable sections which cooperate-to form a chamber for reception of 'a blasting medium, a rupturable connector for joining adjacent ends of said sections in substantially gas tight relation, said connector being designed to rupture upon attainment of a sub stantially predetermined pressure Within said casing, thus permittingseparation of said sectionsand rapid liberation of the blasting medium. Signed at Chicago, Illinois, this 17th'day of Qctober, 1929. Y

. 'FRANK HJKNEELAND.

matters 

